.alpha.-Amino-.alpha.-benzothienylacetic acids (benzothienylglycines) are known compounds, and have been employed in the synthesis of compounds that are useful as antibiotics; see U.S. Pat. No. 3,575,969. The synthesis of benzothienylglycines has been accomplished by several routes, including reduction of .alpha.-oximino-.alpha.-benzothienyl acetic acids that are derived from benzothienylglyoxylic acids; see British Pat. No. 1,399,089. Benzothienylglycines also have been prepared by treatment of a benzothienyl aldehyde with sodium cyanide and ammonium chloride, followed by hydrolysis. This is known as the Strecker synthesis.
All of these synthetic procedures suffer from being non-selective and low-yielding. An object of the present invention is to provide a process that produces 3-benzothienylglycine derivatives in high yield and high purity.